This invention relates to the exothermic generation of oxygen and more particularly to a portable self-contained oxygen generator apparatus and method of generating oxygen well suited for medical and industrial usage.
Emergency medical oxygen is used extensively to meet the requirements of critically ill or injured persons. Small emergency medical oxygen supplies are common in ambulance, fire, police, and medical emergency operations. Generally, emergency medical oxygen supplies are in the form of small tanks containing oxygen at high pressure. These tanks are relatively expensive since they must be equipped with a precision gas regulator and valves to control the flow and pressure of the oxygen during use. Maintaining sufficient numbers of these tanks is sometimes prohibitive because of their cost. In many cases, the requirements of an actual emergency will overwhelm the available number of oxygen supplies, such as during a fire with a large number of smoke-inhalation victims. Moreover, these devices exhibit significant weight so as to be inconvenient to store and handle, and must be refilled after use.
Notably, emergency medical oxygen supplied from such tanks is often of inferior quality. Such oxygen is commonly too dry and can be too cold when the tank has been stored in a cold place. In hospital respirators, expensive systems are utilized to warm and moisturize the oxygen before providing it to the patient. However, such a conditioning of the oxygen is difficult, if not impossible, to achieve during the use of emergency oxygen supplies due to the size and weight of the equipment required to provide such conditioning.
Portable sources of oxygen are also utilized in athletics and industry. For example, athletic teams in such sports as football often provide on-site oxygen supplies for use by the players. Joggers, athletes, and people performing rigorous exercise also have the need for portable sources of oxygen. The need is also present in a wide variety of other diverse applications such as on trains, planes, and boats to counter motion sickness.
The disadvantages of storage tanks render them unacceptable for many applications and, heretofore, portable oxygen generators have also been unacceptable in many respects. In oxygen generators, oxygen-rich chemicals are decomposed in an exothermic chemical reaction to evolve oxygen. Excess heat produced by the chemical reaction is undesirable and may render the oxygen generator hazardous to operate and may render the oxygen produced unacceptable for medical use. For example, hydrogen peroxide is a common oxygen-rich chemical material. Without some means for removing excess heat, the heat generated by the decomposition of hydrogen peroxide is sufficient to generally discourage the use of a solution of hydrogen peroxide having a concentration greater than 10 percent. A solution of hydrogen peroxide greater than 10 percent, when decomposed, would generate an amount of heat sufficient to seriously overheat the oxygen generator. In addition, the vapor pressure of the hydrogen peroxide would be substantial at these elevated temperatures and would represent a significant toxicological problem. Excessive heating would also result in autocatalytic decomposition of the peroxide and can bring about a dangerous runaway reaction. The excessive temperature would also eventually boil the aqueous solution in the generator and excessively heat the product oxygen which would be uncomfortable or dangerously hot to consume in medical applications and would generate large amounts of steam thereby begetting additional problems. Prior means for removing excess heat, such as a heat exchanger, are not desirable in a portable oxygen generator because of size restrictions and severe cost constraints. Such means for controlling excessive heating would be so costly as to greatly restrict the economic utility of such devices.
Consequently, the heat generated by the exothermic reaction has substantially restricted the use of such oxygen generators for medical and industrial applications where convenient portability is required.
The portable oxygen generator apparatus and method of the present invention overcome these and other problems found in prior portable oxygen supplies by providing an oxygen generator comprising a housing having isolated first and second chambers. A predetermined amount of oxygen-generating material is provided in the first chamber of the unit and a predetermined amount of catalyst for activating the oxygen-generating material is provided in the second chamber. A heat-absorbing chemical material is also provided so as to be present during the reaction to absorb the excessive heat released upon the exothermic chemical decomposition of the oxygen-generating material. An admixing apparatus is selectively actuable for selectively admixing the oxygen-generating material into operative contact with the catalyst in the presence of the heat-absorbing material in one of the chambers, being the reaction chamber. A membrane is operationally connected to the reaction chamber to allow the generated oxygen to be expelled from the reaction chamber while retaining the material contents therein.
The method of producing oxygen in accordance with the present invention includes the steps of providing an oxygen-generating material, a catalyst, and a heat-absorbing material, bringing the catalyst and the oxygen-generating material into operative contact to promote the exothermic generation of oxygen gas in the presence of the chemical heat-absorbing material, whereby the temperature of the reaction is controlled without adversely influencing the production of oxygen. The generated oxygen is isolated from and allowed to pass from the site of the exothermic reaction for subsequent use. The chemical heat-absorbing material is present in an amount sufficient to be effective in absorbing a portion of the excessive heat generated by the exothermic decomposition of the oxygen-generating material.
Accordingly, it is an object of the present invention to provide a light-weight, self-contained, high-capacity oxygen generator with an extended shelf life which provides, upon actuation, a steady regulated flow of warm, conditioned oxygen for medical use.
It is a further object of the invention to provide an oxygen generator which is comprised of chemicals that are easy and safe to store and use.
A still further object of the invention is to provide a method for generating oxygen from decomposable oxygen-rich materials which controls excessive generated heat in an economical space-efficient manner.
Yet another object of the invention is to provide an oxygen generator which is economical to manufacture, economical and simple to use, and safely disposable after use.
Other objects will be in part obvious and in part pointed out more in detail hereinafter.